Brush Banding/Posterization in photoshop

[Meppelfield]

Hello,

I ran into a problem last night which I seem to be unable to solve regarding banding and/or posterization with soft brushes in Photoshop. It appeared seemingly out of the blue - I did not actively change anything related to drivers, my computer setup or my monitor and its calibration.

When I use soft brushes I get something that looks like a map of elevation, such as those of the ocean floor. See screenshots below. 
It may or may not have similarities to this issue:

I have switched to 16bit colors in order to attempt to fix this problem (as well as experimenting with color settings, hardware acceleration, and so on) but the problem remains. I honestly do not see much of a difference between 8 bit and 16 bit. See the brown area in particular of my attached screenshot for a view of the problem.

Here is another screenshot:


Do they appear smooth to you or do you see a clear banding effect?

I did not have this issue previously, and I can still open old files that I created prior to the problem occuring and they look good in photoshop.

I have a PC desktop running Windows 10 64bit and Photoshop 19.1.4. It is over 2 years old, and has 16GB of RAM. Its hard drive has 22GB free out of 120GB. The last time I shut down was just before posting this thread. I have never run a cleanup program.

I have checked that I am running in sRGB 16bpc
I have changed my firefox config to view proper colors as of another of your guides.

Best regards
 

[Damien Symonds]

8 minutes ago, Meppelfield said:

I have a PC desktop running Windows 10 64bit and Photoshop 19.1.4. It is over 2 years old, and has 16GB of RAM. Its hard drive has 22GB free out of 120GB. The last time I shut down was just before posting this thread. I have never run a cleanup program.

Probably not related to the problem, but 22GB is well short of the minimum 1/3rd free space that Brian always recommends.  You definitely must run Glary or similar - such an old machine will have a LOT of clutter on it.  Also, taking the time to run this will be very beneficial.

10 minutes ago, Meppelfield said:

I did not have this issue previously, and I can still open old files that I created prior to the problem occuring and they look good in photoshop.

We need to explore this.  These old files you tried opening - were they very similar to this one?  That is, black with very faint colour painted on them?  No other sample image will do.  This problem is VERY specific to this kind of file.

Which brings me, of course, to another question - how often do you do this kind of work?  I mean, black with other colours painted on faintly?  I'm trying to glean how certain you are that this is a new problem.

[Meppelfield]

21 hours ago, Damien Symonds said:

Probably not related to the problem, but 22GB is well short of the minimum 1/3rd free space that Brian always recommends.  You definitely must run Glary or similar - such an old machine will have a LOT of clutter on it.  Also, taking the time to run this will be very beneficial.

I ran what you suggested and it freed up quite a bit of space and flagged a number of issues that it fixed. I do not see any immediate effect, but I suppose it is good to keep things tidy.
 

21 hours ago, Damien Symonds said:

We need to explore this.  These old files you tried opening - were they very similar to this one?  That is, black with very faint colour painted on them?  No other sample image will do.  This problem is VERY specific to this kind of file.

Which brings me, of course, to another question - how often do you do this kind of work?  I mean, black with other colours painted on faintly?  I'm trying to glean how certain you are that this is a new problem.

The files I submitted in my original post were designed that way to make the problem I'm seeing as evident as possible. It is still a problem, although less obviously so, in other scenarios. My previous files that I created had way more stuff going on, so I am not sure how comparable they would be.

Funnily enough, your response was enough to make me take a slightly different approach to my fault tracing and I think I have narrowed things down a bit. I have done a majority of my previous work in 8 bit colors. For this piece I was about to start working on I knew there would be a lot of focus on skin tones, so I switched to 16 bit colors in order to enable smoother transitions and make it look realistic. As I was starting off I wanted to make my own gradient through brushing, so I started with a very dark background and wanted to gradually brighten it through brush strokes, which is when I discovered the very dark banding as I showed in my original post. I couldn't look past it as it was so disturbing to my eyes.

Today I opened one of my old files that i finished some time ago, sRGB 16 bit, and tried converting it to 8 bit instead. To my surprise I couldn't see a single thing changing. I toggled between undo and redo for a while but there was no change whatsoever. I then proceeded to create gradients (using the gradient tool) from black to white in two new documents, one 8 bit and one 16 bit. The 8-bit version actually looks better, because it applies dithering which the 16-bit does not. I am not sure really what's going on at this point.

For now, I will continue to work in 8-bits, because I think I can adapt so that it suits my needs. But I am still confused as to why I see no improvement from working in 16-bit. The way I understood it is that you get a way wider color range at your disposal but it will make your files larger and heavier to work with. Do you have any theory as to why I am experiencing this? Does it make sense to you at all?

[Damien Symonds]

51 minutes ago, Meppelfield said:

For now, I will continue to work in 8-bits, because I think I can adapt so that it suits my needs. But I am still confused as to why I see no improvement from working in 16-bit. The way I understood it is that you get a way wider color range at your disposal but it will make your files larger and heavier to work with. Do you have any theory as to why I am experiencing this? Does it make sense to you at all?

Well, we need to clarify the difference between the file itself, and how you're viewing it.  I have no doubt that your 16-bit file is as perfect and smooth as you'd expect it should be.  But no matter whether your file is 16-bit, 20-bit, 100-bit, or even a thousand-bit, you're still only viewing it on your screen.  And your screen, unless you've spent big money on one of those 10-bit jobs, is 8-bit at most.  (Some older screens were even lower!).

I don't profess any great technical expertise in this matter.  But my guess is that you're right, in a roundabout way, about the dither on the 8-bit file.  The dither is helping your screen, as much as the file itself.

Does this seem plausible?

[Meppelfield]

On 2018-05-30 at 12:56 AM, Damien Symonds said:

Does this seem plausible?

Yes, it does.

First of all, sorry for the delay in answering here. Something came up and I had to take a few days off around the weekend.

I believe that I may have mislead myself a bit by reading posts on other forums saying that "you will see less banding in 16-bit" when they may well have been refering to something like a printed piece that actually is not limited in the same way a typical monitor is.

I think we can close this issue, and I would like to sincerely thank you for your help.

I wish you all the best

[Damien Symonds]

Any further occurrences of this problem, @Meppelfield?